Description

Kingson £sd calculating machine (or stylus-driven addiator) used for addition and subtraction of Sterling. Plastic case. Stylus missing.

British pre-decimal currency was based on pounds, shillings and pence. There were 12 pence to the shilling and 20 shillings to the pound. The calculator has three columns representing these units.

Before beginning a calculation reset the calculator by pulling up the reset bar at the top of the device and ensure all columns are set to zero.

To add, set the first value in the columns using the stylus. If the number slot is white, pull the stylus down towards the bottom until it stops and – if coloured red – push the stylus up and loop it round the curved “hook” at the top. To add subsequent numbers, follow the same rules using the Addition portion of the device.

To subtract, use the same process to enter the first value but use the Subtraction portion of the device.

The device can be used for continuous addition and subtraction.